The described patch causes the error message to disappear.
More testing could be useful.
This is what I did:
-- deleted the plugin dokuwiki: directories in <public_html> and <geeklog> are NOT deleted
-- removed the residue directories by hand (in /dokuwiki, /admin, /plugins)
-- installed the plugin again as described
-- experimenting:
---- use of timeout == 2: no luck
---- suppressing error messages: no luck
---- patch as described: bingo.
It seems to me that the error is triggered when getting the feeds at dokuwiki.org, which is default and standard.
These feeds show several new releases since "Rincewind", wich dates back to 2011.